The present invention relates to a method and apparatus for manufacturing an article in the form of a scroll for use in a compressor or like device incorporated in an air-conditioning equipment.
As a method for manufacturing a scrollwork has been known, for example, the method as disclosed in Japanese Unexamined Patent Publication No. 62-88507. This method is such that a tool is brought into contact with an inner or outer wall surface in the form of an involute curve of the work along an X-axis normal to a Y-axis corresponding with a radial direction of a basic circle of the involute curve with the center of the tool being displaced from the center of the basic circle along the Y-axis by the radius of the basic circle, and the work is rotated about the center of the basic circle while moving the tool and the work relative to each other along the X-axis, thereby processing the wall surface.
According to this method, the wall surface can be processed by moving the tool and the work relative to each other along the X-axis and rotating the work.
When the inner and outer wall surfaces in the form of the involute curve are processed one after the other in manufacturing the scrollwork, the direction in which the tool is brought into contact with one wall surface is opposite from the direction in which the tool is brought into contact with the other wall surface (180.degree.) if the conventional method is simply applied. This causes a variety of difficult problems in correcting the positional relationship between the tool and the work during the processing. More specifically, when the positional relationship between the tool and the work deviates from a predetermined one due to mechanical or thermal factor, this results in an error in the contour of the involute curve portion. It is desirable to easily correct this positional relationship based on the contour error to thereby satisfactorily maintain the processing accuracy.
However, both the inner and outer wall surfaces of the scrollwork are generally formed into an involute curve. When the both wall surfaces are processed according to the above method, the correlation between the deviation of the positional relationship of the tool and the work and the contour error resulting therefrom tends to be complicated. The complicated correlation makes it difficult to conduct the above correction by a simple measurement.